Please help and with steps. I suck at these and really don’t understand them

Answer:
see explanation
Step-by-step explanation:
The n th term of an arithmetic sequence is
[tex]a_{n}[/tex] = a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = 10 and d = - 3, hence
[tex]a_{n}[/tex] = 10 - 3(n - 1) = 10 - 3n + 3 = - 3n + 13, so
[tex]a_{n}[/tex] = - 3n + 13 ← n th term formula